U.S. patent number 9,375,729 [Application Number 13/521,142] was granted by the patent office on 2016-06-28 for cassette and system component insertable into a centrifuge in cooperation with the cassette.
This patent grant is currently assigned to Andreas Hettich GmBH & Co. KG, Terumo BCT, Inc.. The grantee listed for this patent is Roland Biset, Klaus-Gunter Eberle, Wilfried Mertens. Invention is credited to Roland Biset, Klaus-Gunter Eberle, Wilfried Mertens.
United States Patent |
9,375,729 |
Eberle , et al. |
June 28, 2016 |
Cassette and system component insertable into a centrifuge in
cooperation with the cassette
Abstract
The invention pertains to a cassette (2) comprising a product
conveying path (1, 1a, 1b) and a positioning means (3a, 3b)
engageable with a counter-piece on a centrifuge having a rotor for
separating blood components or on a system component (4) arranged
in a centrifuge. The positioning is effected such that a section of
the product conveying path (1, 1a, 1b) is aligned with a section of
the centrifuge or the system component arranged in the centrifuge.
Furthermore, a tube connected with bags is accommodated in the
product conveying path (1, 1a, 1b).
Inventors: |
Eberle; Klaus-Gunter
(Tuttlingen, DE), Biset; Roland (Leuven,
BE), Mertens; Wilfried (Leuven, BE) |
Applicant: |
Name |
City |
State |
Country |
Type |
Eberle; Klaus-Gunter
Biset; Roland
Mertens; Wilfried |
Tuttlingen
Leuven
Leuven |
N/A
N/A
N/A |
DE
BE
BE |
|
|
Assignee: |
Terumo BCT, Inc. (Lakewood,
CO)
Andreas Hettich GmBH & Co. KG (Tuttlingen,
DE)
|
Family
ID: |
43857882 |
Appl.
No.: |
13/521,142 |
Filed: |
January 5, 2011 |
PCT
Filed: |
January 05, 2011 |
PCT No.: |
PCT/EP2011/050094 |
371(c)(1),(2),(4) Date: |
November 13, 2012 |
PCT
Pub. No.: |
WO2011/083120 |
PCT
Pub. Date: |
July 14, 2011 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20130130883 A1 |
May 23, 2013 |
|
Foreign Application Priority Data
|
|
|
|
|
Jan 8, 2010 [DE] |
|
|
10 2010 000 752 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61M
1/3693 (20130101); B04B 5/0428 (20130101); A61M
1/0209 (20130101); A61M 2205/12 (20130101); B04B
2005/0435 (20130101) |
Current International
Class: |
B04B
5/04 (20060101); A61M 1/36 (20060101); A61M
1/02 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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196 22 050 |
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DE |
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100 65 283 |
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DE |
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11 2004 000 569 |
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DE |
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103 16 598 |
|
May 2008 |
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DE |
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102007000308 |
|
Dec 2008 |
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DE |
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102007000309 |
|
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DE |
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102007000310 |
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DE |
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0499891 |
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EP |
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0616816 |
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EP |
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1351772 |
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EP |
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1512464 |
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1557187 |
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2174149 |
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GB |
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02053292 |
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WO |
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03089027 |
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WO |
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2004069310 |
|
Aug 2004 |
|
WO |
|
2007024550 |
|
Mar 2007 |
|
WO |
|
2010061863 |
|
Jun 2010 |
|
WO |
|
Other References
International Search Report dated Sep. 25, 2008 for
PCT/EP2008/056926. cited by applicant .
International Search Report dated Sep. 25, 2008 for
PCT/EP2008/056923. cited by applicant .
International Search Report dated Oct. 14, 2008 for
PCT/EP2008/056925. cited by applicant .
International Search Report; International Application No.
PCT/EP2011/050094; International Application Filing Date Jan. 5,
2011; Mail date May 2, 2011. cited by applicant .
Written Opinion; International Application No. PCT/EP2011/050094;
International Application Filing Date Jan. 5, 2011; Mail date May
2, 2011. cited by applicant .
International Preliminary Report on Patentability; International
Application No. PCT/EP2011/050094; International Application Filing
Date Jan. 5, 2011; Date of completion of this report Apr. 4, 2012.
cited by applicant .
Millipore Corp.: MulitiScreen Assay System, Centrifuge Alignment
Frame, User Guide, 2008. cited by applicant.
|
Primary Examiner: Cleveland; Timothy
Attorney, Agent or Firm: Merkling; John R.
Claims
The invention claimed is:
1. A cassette comprising: a product conveying path; and a
positioning means engageable with a counter-piece on a centrifuge
having a rotor for separating blood components or on a system
component arranged in the centrifuge such that a section of the
product conveying path is aligned with a section of the centrifuge
or the system component arranged in the centrifuge, wherein a tube
connected with bags is accommodated in the section of the product
conveying path; wherein the positioning means is provided in the
form of one or plural bars arranged in the direction of the section
of the product conveying path, and the one or plural bars are
arranged in a window.
2. A cassette according to claim 1, comprising a lower part and an
upper part, wherein the positioning means is formed in the lower
part or in the upper part, or in both.
3. A cassette according to claim 2, wherein the lower part and the
upper part are connectable to each other by a connecting means and
the product conveying path is provided in the form of a
passage.
4. A cassette according to claim 1, wherein at least one shut-off
device for interrupting a product flow is provided on the product
conveying path.
5. A cassette according to claim 4, wherein the at least one
shut-off device is integrated into a lower part or into an upper
part of the cassette.
6. A cassette according to claim 4, wherein the at least one
shut-off device is provided at a rim of the cassette and is
directly operable from outside the cassette.
7. A cassette according to claim 4, wherein the at least one
shut-off device is provided in the form of one or two tube clamps,
which can be operated separately from each other.
8. A cassette according to claim 1, wherein the cassette comprises
connecting means for establishing a connection with a cartridge
accommodating the cassette, said cartridge being adapted to be
accommodated in the centrifuge or in the system component arranged
in the centrifuge.
9. A system comprising a centrifuge for separating blood components
and a cassette for being arranged in said centrifuge for separating
blood components, the centrifuge comprising: a rotor rotatable
around a hub, and a counter-piece, wherein the counter-piece is
provided in the form of an elevation having one or plural grooves
in the wall sections of which one or plural sensors are arranged,
and the cassette comprising: a product conveying path; and a
positioning means engageable with the counter-piece on the
centrifuge for separating blood components or on a system component
arranged in the centrifuge such that a section of the product
conveying path is aligned with a section of the centrifuge or the
system component arranged in the centrifuge, wherein a tube
connected with bags is accommodated in the product conveying path;
wherein the positioning means is provided in the form of one or
plural bars arranged in the direction of the section of the product
conveying path, and the one or plural bars are arranged in a
window.
10. The system according to claim 9, further comprising an
operating means for operating a lock-off device disposed in the
cassette.
11. The system according to claim 10, wherein the operating means
is provided in the form of a centrally arranged, long lever having
an end and at least one short, L-shaped lever arranged at the end
of the long lever, the end of the long lever being directly
operable by a first piston, or indirectly by a second piston and a
leg of the short, L-shaped lever.
12. The system according to claim 9, wherein the one sensor or the
plural sensors are formed as light sensitive sensors, and by
engaging the positioning means of the cassette with the
counter-piece, a central axis of the tube accommodated in the
product conveying path of the cassette is exactly aligned to the
optical axis or optical axes of the light sensitive sensor or of
the light sensitive sensors.
Description
TECHNICAL FIELD
The invention relates to a cassette used as cover for accommodating
blood bags for a cartridge of a centrifuge for separating blood
components, and a system component insertable into such a
centrifuge in cooperation with the cassette.
BRIEF DISCUSSION OF RELATED ART
In transfusion medicine, the so-called blood component therapy has
established itself since the beginning of the nineties. This means
that, instead of a whole blood conserve, only those blood
components required by the individual patient are administered to
said patient. This separate administering of the individual blood
components makes it possible that one single blood conserve
optimally helps an average of 1.8 patients.
The essential blood components are the red blood cells in the
so-called erythrocyte concentrate, which are transfused in order to
maintain the oxygen supply after severe loss of blood, the blood
platelets in the thrombocyte concentrate, which are administered in
cases of coagulation disturbances (haemophilia), and the blood
plasma, which is administered in cases of coagulation disturbances
and volume deficits.
Apart therefrom, blood plasma is an essential basic component for
the production of many medicaments.
The separation of the individual blood components, which is defined
as cell separation/isolation, is known to be effected by treating
the blood in a centrifuge. By means of centrifuging, the individual
blood components are separated from each other, and can then be
separately filled into the respective containers for further
use.
Documents DE 10 2007 000 308 A1, DE 10 2007 000 309 A1 and DE 10
2007 000 310 A1 already reveal a cartridge for use in a centrifuge
for separating blood components and a respective centrifuge as well
as a respective method. According to these documents, a cartridge
comprises an intermediate wall and a cover. The intermediate wall
separates a blood bag area disposed radially inside from a product
area disposed radially outside. In an installation position of the
cartridge, the cover is located above the blood bag area. The cover
is connected to the intermediate wall pivotally at one point, and
detachably at a second point. In this way, the blood bag area is
freely accessible by a lateral turning away of the cover. For
loading the cartridge with a blood bag, the cover is opened, a
blood bag and a product bag are inserted into the respective
chambers, and a connecting tube is inserted along a product
conveying path. Moreover, photosensitive sensors are arranged along
the product conveying path and are used to establish the
composition of the product while the product is obtained; when a
specific composition is reached, measures are taken for terminating
the obtaining of the product. However, loading of the cartridge may
only be effected manually, which renders it time- and
cost-consuming. Besides, there is the possibility that the product
is destroyed upon a faulty insertion of the connecting tube, since
the sensors do not react timely.
Therefore, the known means need to be improved such that, on the
one hand, faulty loading is avoided and, on the other hand, time is
saved.
BRIEF SUMMARY
According to the invention, a cassette is provided, comprising a
product conveying path in the form of a passage and a positioning
means engageable with a counter-piece on a centrifuge or on a
system component arranged in a centrifuge such that a section of
the product conveying path is aligned with a section of the
centrifuge or the system component arranged in the centrifuge. A
tube connected with bags is accommodated in the product-conveying
path.
Thus, according to the invention, cassettes with the already
inserted tube and two or more bags (one blood bag and at least one
product bag) attached to the tube can be supplied to a user in the
form of a kit. Thus, after a blood collecting process, the cassette
comprising the tube and the bags can be inserted into a system
component of a centrifuge, or directly into the centrifuge to
perform a centrifugation process in which the blood in the one bag
is separated and at least one of the separated blood components is
transferred into the second bag.
After this centrifugation process has been completed, it is merely
necessary to replace the cassette present in the centrifuge by a
new one and to subject the old cassette to further processing. In
this respect it is noted that, in general, any number of cassettes
can be subjected to the centrifugation process. Preferably a number
of six cassettes is processed simultaneously in the centrifuge.
Since the tubes and bags are replaced together with their related
cassette, a remarkable reduction of dead time is achieved.
The exact alignment of the connecting means with the counter-piece
makes it possible to reach an exact alignment of the product
conveying path with the respective section of the centrifuge or the
system component. This ensures that photosensitive sensors arranged
in the section of the system component can detect the product
flowing through the product conveying path anytime. Thus,
appropriate reactions, e.g. for terminating the production process
are promptly possible, without delay. In particular, the section of
the product-conveying path and/or tube arranged directly adjacent
to the positioning means can be exactly positioned to be directly
adjacent to the counter piece where the sensors are provided.
Furthermore, due to the positioning means, it is ensured that an
axis of the sensors substantially intersects a central axis of the
product conveying path at a right angle.
Advantageously, the cassette may comprise a lower part and an upper
part which are connected to each other by snap elements or other
means. It is also possible that the positioning means is only
formed in the lower part, only in the upper part, or in both. Other
means in terms of the invention may e.g. be screw joints and/or
rivet joints or bonded joints.
Preferably, the positioning means is provided in the form of one or
plural bars arranged in the direction of one or plural sections of
the product conveying path. The bars can be arranged in a window.
Such an arrangement can be easily manufactured, and can easily
establish a form-fit connection with an appropriately formed
counter-piece.
Advantageously, at least one shut-off device for interrupting a
product flow can additionally be provided at one or plural sections
of the product conveying path. The shut-off device makes an abrupt
termination of the production process possible. The maximally
possible portion of the desired product, e.g. thrombocytes, can be
gained before the product is contaminated by undesired blood
components.
Advantageously, the at least one shut-off device can be integrated
into the lower part or into the upper part of the cassette, and can
be operated directly from outside the cassette. This allows a quick
and safe operation of the shut-off device without the danger of a
failure, which may otherwise occur by a faulty insertion of the
shut-off device. The operation of the shut-off device can be
effected manually or mechanically, e.g. by means of actuating
members operated pneumatically, hydraulically or
electronically.
Advantageously, the at least one shut-off device can be provided in
the form of one or two tube clamps, which can be operated
separately from each other.
Besides, the cassette may comprise connecting means for being
connected to a cartridge, which can be accommodated in the
centrifuge or the system component arranged in the centrifuge.
Accordingly, the cassette fulfills a function as cover of the
cartridge.
Advantageously, the cassette according to the invention is
accommodated in a system component for arrangement in a centrifuge
for separating blood components, with a rotor rotatable around a
hub. The system component comprises a counter-piece which can be
engaged with a positioning means of the cassette. In this way, an
exact positioning of a section of the product conveying path to a
section of the system component is ensured.
The counter-piece may be provided in the form of an elevation
having one or plural grooves in the wall sections of which one or
plural sensors are arranged. Preferably, these are photosensitive
sensors/photosensors.
Additionally, the system component can comprise an operating means
for operating a lock-off device disposed in the cassette. The
operating means can preferably be provided in the form of a
centrally arranged, long lever having two ends and two short,
L-shaped levers arranged at the ends of the long lever. Each end of
the long lever is directly operable by a first piston, or
indirectly by a second piston and a leg of the short, L-shaped
lever.
Preferably, the cassette and the system component can be used in a
centrifuge for separating blood components, having a rotor of a
centrifuge rotatable around a hub. The system component is
accommodated in the rotor, or integrated into the same. Moreover, a
cartridge can be incorporated into the system component, and this
cartridge can be provided with a cassette loaded with a blood bag
and a product bag. The cassette is used as cover for a blood bag
area of the cartridge.
The use of a cassette according to the invention and the system
component according to the invention allows to obtain one or also
plural blood products, such as plasma, erythrocytes, or
thrombocytes. This may be obtained particularly in that a
microprocessor can be provided in the system component to be used
for controlling and monitoring the product extraction process.
Then, by means of the microprocessor, particularly the detection
results of the sensors can be processed and the operations of the
shut-off devices can be carried out accordingly. Advantageously,
the microprocessor in the system component can furthermore be
connected to another microprocessor accommodated in the rotor of
the centrifuge, which is adapted to carry out the control and the
monitoring of the entire product extraction process.
BRIEF DESCRIPTION OF THE DRAWINGS
Further advantages of the invention can be seen from the
description of a currently preferred embodiment and the Figures
attached. Referring to the Figures,
FIG. 1 shows a top view of a lower part of a cassette according to
the invention;
FIG. 2 shows a sectional view along a line II-II in FIG. 1;
FIGS. 3a and 3b show a top view and a view of a detail III from
FIG. 1, respectively;
FIG. 4 shows a sectional view along a line IV-IV in FIG. 1,
FIG. 5 shows a top view of an upper part of a cassette according to
the invention;
FIG. 6 shows a sectional view along a line VI-VI in FIG. 5;
FIG. 7 shows a sectional view along a line VII-VII in FIG. 5;
FIG. 8 shows a view of a cassette according to the invention, said
cassette being provided in a system component according to the
invention.
DETAILED DESCRIPTION
A currently preferred embodiment of the invention is described by
means of FIGS. 1 to 8.
A cassette 2 according to the embodiment is composed of a lower
part 5 and an upper part 7 which are connected to each other by
means of snap elements 9 and 13, and 11 and 15, respectively. The
upper part is made of a transparent material. Besides, as can be
seen from the Figures, the cassette 2 is provided approximately in
the form of a rectangle having two arms 35a, 35b.
The lower part 5 as well as the upper part 7 of the cassette 2
comprises a window 17 in a central area of the rectangle. Moreover,
in the upper part 7, two bars 3a, 3b are formed to be used as
positioning means according to the invention. The bars 3a, 3b
extend along a partial section of a product-conveying path 1.
A channel-type passage 1 is formed as product-conveying path 1 in
the lower part 5. The passage 1 is divided into two sections 1a and
1b. At one edge of the lower part 5 opposite the arms 35a, 35b, two
tube clamps 19a, 19b are integrated into the lower part 5.
A tube (not shown in the Figures) provided with a blood bag, a
filter and a product bag is laid in the product-conveying path 1
such that the tube is conducted from the blood bag disposed between
the arms 35a, 35b to the first section 1a, along the bar 3a,
through the tube clamp 19a arranged in the first section 1a further
to the arm 35a. The tube then emerges from the arm 35a, leads to
the filter, and enters via the second arm 35b the second section 1b
of the passage 1. Then, the tube is led along the bar 3b, through
the tube clamp 19b and again the arm 35b, in order to emerge from
the same towards the product bag.
At each of its arms 35a, 35b, the cassette 2 comprises a projection
21a, 21b disposed inside, which is used to detachably fix the
cassette to a non-represented cartridge similar to the one in
documents DE 10 2007 000 308 A1, DE 10 2007 000 309 A1 and DE 10
2007 000 310 A1. The blood bag, the filter and the product bag are
then accommodated in appropriate chambers of the cartridge. The
cassette 2 replaces a cover in the said applications.
Together with the cassette 2, the loaded cartridge is inserted into
a system component 4 that is arranged in a centrifuge. An elevation
25 in which two grooves are formed is provided in a section of the
system component 4. Photosensitive sensors 23a, 23b are inserted
into the inner walls of each groove.
If the cassette 2 is disposed in the system component 4, the
elevation 25 is engaged in a form-fit connection with the window
17, and the bars 3a and 3b with the grooves formed in the elevation
25. The sections of the tube extending along the bars 3a, 3b are
disposed directly below the bars 3a, 3b, whereby the contents of
the tube can be exactly registered by the photosensitive sensors
23a, 23b. The first photosensitive sensor 23a is assigned to the
first section 1a of the product-conveying path 1, whereas the
second photosensitive sensor 23b is assigned to the second section
1b of the product-conveying path 1. The optical axes of the
photosensitive sensors 23a and 23b substantially intersect the
central axis of the product conveying path (the tube) at a right
angle.
Since the tube does not have to be inserted into the cassette 2 any
more, but the cassette is already delivered together with the
readily laid tube including blood bag, filter and product bag, a
faulty insertion of the tube or a displacement of the tube that
would lead to a faulty registration by the sensors can be reliably
excluded.
Thus, it is possible, due to the interaction of the cassette
according to the invention with the system component, to obtain a
blood product by means of the method disclosed in document DE 10
2007 000 309 A.
According to the embodiment, the rotor of the centrifuge is
designed for six system components 4 having one cartridge each.
After all cartridges loaded with cassettes 2 have been inserted,
the centrifuge is started. By means of the centrifugal force, the
desired separation of the blood components is effected. Since the
"buffy coat" diluted by an additive solution is in the blood bag,
the lighter components of it will remain radially inside, whereas
its heavier components, i.e. the red blood cells, collect
outside.
In order to transport the desired blood component--according to the
embodiment, these are the platelets (thrombocytes)--in high
quality, i.e. without the admixture of other blood cells, from the
blood bag, the separation of the components will be followed by a
slight pressure being applied onto the blood bag by means of a
pressure pad, so that, after the previously closed tube clamps 19a,
19b have been opened, the solution rich in platelets begins to rise
into the tube disposed in the passage 1. The solution rich in
platelets is led through the tube into the filter designed as a
leukocyte filter, and is further conducted therethrough.
In the leukocyte filter, the undesired leukocytes, i.e. the white
blood cells, are removed. Due to the arrangement of the tube with
the filter, the filtration is effected against the centrifugal
force. Thus, heavier blood components, such as unintentionally
transported red blood cells, are trapped in a filter-inlet chamber
positioned radially outside.
After having passed the leukocyte filter, the solution rich in
platelets continues flowing through the tube laid in the second
section 1b of the passage 1 into a product bag, in which it is
collected. Preferably, the product bag is already formed as final
storage bag for the product.
In order to remove any air that might be present in the filter, the
flow speed is kept low for a certain volume quantity at the
beginning of the product transfer, thereby enabling the filter to
fill with the blood product reliably and completely. After the
transfer of this specific volume quantity, the conveying speed for
a specific second volume quantity is increased by means of an
appropriate control of the pressure pad. While this second volume
is transported, there is hardly any risk that red blood cells
contaminate the blood product (here: the thrombocyte concentrate).
Should this nevertheless happen, this small number of red blood
cells are collected in the lower and outer area of the filter, due
to the tube being guided from radially outside and below into the
filter, and due to the effect of the centrifugal force.
After the second volume has been transferred, the first photosensor
23a is activated and the flow speed of the blood product in the
tube is reduced.
When the first photosensor 23a detects a predetermined proportion
of red blood cells in the thrombocyte-rich solution, it outputs a
signal by means of which the flow speed is again reduced.
Furthermore, the second photosensor 23b disposed behind the filter
is activated.
During this phase, also a rather large number of red blood cells
can enter the filter and even pass therethrough until the second
photosensor 23b detects a predetermined proportion of red blood
cells in the blood product and outputs a signal for terminating the
cell separation process. By this signal, the tube clamps 19a, 19b
are closed by operation of the ends 29a, 29b of a long lever 29 by
means of pistons 31a, 31b, so that the red blood cells in the
filter are reliably separated from the thrombocyte concentrate in
the product bag.
As an alternative to the termination by the second photosensor 23b,
the cell separation process can also be terminated after a certain
period of time has elapsed after the activation of the second
photosensor 23b.
In the embodiment, altogether six cartridges are provided in the
centrifuge. The above-described control of the cell separation
process in a cartridge 1 by means of a pressure pad, the opening
and closing of the tube clamps 19a, 19b, and the process control by
means of the two photosensors 23a, 23b enables a continued cell
separation in the cartridges of the other system components, since
the described process control takes place individually for each
combination of cartridge and system component.
The control of the process is effected by a microprocessor provided
in the system component, said microprocessor processing the
detection/registration results of the sensors 23a, 23b and
accordingly controlling the opening and closing of the tube clamps
19a, 19b by operating the levers 31a, 31b and 33a, 33b,
respectively. Besides, the microprocessor is connected to a
microprocessor arranged in the hub of the rotor for controlling the
centrifuge and monitoring the microprocessors in the individual
system components.
When the above-mentioned process is carried out, a precise
operation of the tube clamps 19a, 19b is required for ensuring an
optimum yield while simultaneously avoiding a contamination of the
product. For operating the tube clamps 19a and 19b integrated in
the lower part 5 of the cassette 2, the invention provides, in the
system component, an arrangement having a centrally arranged long
lever 29 and L-shaped, short levers 27a, 27b arranged at the two
ends 29a and 29b of the long lever 29. The ends 29a, 29b of the
long lever are disposed between a leg of the short lever 27a, 27b
and a closing arm 191 of the tube clamp 19a and 19b,
respectively.
At its central section, the long lever 29 is fixed to the system
component 4. The short levers 27a, 27b are pivotally supported
around the intersection of the two legs of the "L". The entire
lever arrangement is disposed along the edge of the cassette 2, on
which the tube clamps 19a, 19b are arranged when the cassette is
inserted into the system component.
Pistons 31a, 31b, 33a, 33b, which are suitably arranged in the
system component 4, are used for operating the levers 27a, 27b and
29. The pistons 31a, 31b directly act on the respective end 29a,
29b of the long lever. The pistons 33a, 33b directly act on a leg
of the short levers 27a and 27b, respectively, said leg being
disposed between the pistons 33a and 33b and the respective ends
29a, 29b of the long lever 29.
Since the ends 29a, 29b of the long lever 29 are disposed directly
opposite the closing arm 191 of the tube clamps 19a and 19b when
the cassette is inserted, an operation of the piston 31a or 31b
leads to the closing of the respective tube clamp 19a or 19b.
Since, in turn, an operation of the pistons 33a, 33b acts on the
one leg of the rotatably supported, short levers 27a and 27b,
respectively, this operation leads to a twisting of the levers 27a
and 27b, respectively. The leg disposed between the pistons 33a and
33b acts on the end 29a or 29b of the long lever 29, whereas the
other leg of the short lever 27a or 27b acts on an opening arm 192
of the tube clamp 19a or 19b, thereby opening the same. The
indirect operation of the ends 29a, 29b of the long lever serves to
exclude that the tube clamp bursts open too suddenly or too wide,
so that problems e.g. due to the tube clamps getting jammed can be
avoided.
The invention has been described by means of a currently preferred
embodiment, but is not restricted thereto in any way, but only
defined by the scope of the claims attached.
* * * * *